Is a map like this useful?

[dorentir]

The maps you have shown are fantastic. I've experimented a little in making maps like this of towns like this one:
http://www.blind-eye.com/images/Tarantis_godseye_map.jpg
But mine are a lot cruder in comparison to yours. I was inspired by some medieval maps I saw of different cities where you could see the buildings. Since I want my settings to be relatively consistent, I actually find the more time I spend on the drawing the less time I need to spend on writing a key and looking at the map itself can help me describe the place much quicker --- I just glance at the map and say, "this part of town seems to have more temples in it... you enter a courtyard with a fountain and see a large, impressive temple with pillars and a blue tile roof..." How many notes would I have to flip through to dig that up?
If you think of it on terms of isometric perspective the drawing will look less like an aerial view but one can measure distances on the map and get close enough for gaming purposes.

 

[Odhanan]

This is a close up of the thing at the center of the second map. It is also in color!

The coloring has a Tolkien feel to it, if you've seen his own artwork before. I like it very much.

 

[Bobitron]

I think all the examples you posted are great! A 'flat' map for measurement isn't really needed in my opinion, especially if the setting can provide a grid like in an atlas showing the distances between cities.